WOOSTER (AP) — A message on a high school bathroom wall that included a swastika and the phrase “kill them all” has prompted a police investigation and heightened security throughout a northeastern Ohio district.

The threat mentioning Thursday’s date was found after school on Tuesday at Wooster High School, about 50 miles southwest of Cleveland.

Wooster school officials say the threat seems to have little credibility, but they are taking it seriously as they continue classes with extra security.

Superintendent Michael Tefs tells The Daily Record in Wooster that those security changes include keeping school buildings on lockdown and not having recess.

He says officials are reviewing security camera footage to identify which students were in the restroom before the message was found.